Wiring up a new enternally regulated alternator quick! - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Reumster · 03-13-2003, 01:58 PM

Ok I just fried a battery because I was running with a bad voltage regulator, but I'm waiting on a new M&H harness that converts old style to internally regulated. I bought a internally regulated alternator and need to do a quick wire job. How do I do it?

68speedalert · 03-13-2003, 02:21 PM

I assume you are puttin on an older delco alt. If so, go to most parts stores and buy the 2 wire connector that plugs into the reg. on the alt. the large red on the conn goes to the large battery terminal on the alt. I'm sure you realize the large feed wire from the truck hasrness still goes there.

Here's the tricky part. Some alts don't need a sense signal but others do. To the small white wire on the reg. connector you need to wire a key on hot wire with either a diode online or a 10 ohm resistor. If you don't, your truck won't shut off!!!!!

Steve

Reumster · 03-13-2003, 02:30 PM

I have the first internally regulated alternator, like a 73 or something.

So the two prong connector coming of the alternator red wire needs to go to the power on the alternator also put the existing wire on the stock harness there to.

The second white wire coming off the alternator connector goes to a acc. on the fuse box with a diode in line. Why so power won't back feed? I have plenty of schottky diodes only let power flow one direction. Will this due? Power to the alternator not back to the fuse box right? I have a 10ohm resistor to. Which is better? The diode right.

my new 72 · 03-13-2003, 03:09 PM

That diode thing is pretty unnecessary. The red wire from the pigtail goes to the post on the back of the alternator, as well as the red bat. feed wire. Then the white wire goes to the white wire from the original alt. plug. The blue wire left over from the old alt. plug gets taped off. Then you use jumper wires to jump the wires on the voltage regulator connector like so. But since I forgot the picture, all you really have to do is jump the white to the brown on the volt reg connector.

my new 72 · 03-13-2003, 03:13 PM

forgot the pic

68speedalert · 03-14-2003, 08:47 AM

josh,

good job on the jumping of wires at the reg connnector. I haven't switched my truck to int. reg yet even though I have the alt to do it. I'll remember your trick.

My switchover was on an older jeep that I owned 20 years ago. Different regulators in the alt are sometimes different, depending on what they came off of. The one I had would back feed voltage to the ignition system after it started charging thru the white wire. So whenever i turned the key off, it didn't. When researching the wiring schematic on that gm car, they showed a 10 ohm resistor inline on that circuit. Back then I didn't know what a diode was so i put in the resistor and had no problems after. There are regulators you can buy that don't need the white wire(key on sense wire).

reumster, if you still need to use the diode I would use it. Make sure it allows the voltage TO the reg.

good luck.
Steve

Reumster · 03-14-2003, 03:01 PM

Thanks for the info but my M&H new harness from Early Classic got in, and I installed it so its allready done for me. Works great. This harness fit like a glove. Perfect.

Xzavior240 · 03-14-2003, 03:24 PM

ok I done went crosseyed trying to understand this. I see the part about the reg. on the rad. support. anyone got a pic or harness diagram showing the alt. ? because I have the alternator on the motor and everything. I just keep getting confused with jump this from here to that and cross this and add that and make this go to there.

thanks
dan

barn9 · 03-14-2003, 06:14 PM

Xzavior240, I have the adaptor available to change over to the internally regulated alternator and eliminate the old voltage reg. It does have the diode wired into it also, which IS needed IMO. It's an easy changeover this way, and does not require any more than a couple wire splices. I'll add a pic of my alt to show the adaptor, but it doesn't show the connections very well.

Xzavior240 · 03-14-2003, 06:49 PM

ok youre right barn9 it doesnt show really well what I can see from it is the red wire hooking to the hot as well as the original wire and the white going onto the other side of that connection wheres the blue go? thanks for the attempt none the less

barn9 · 03-15-2003, 04:07 AM

The wires from the original harness go like this:
Blue-unused, just clip it and forget it.
Black-unused
Red-ground wire.
White (switched lead)-spliced to the white wire on the adaptor plug.

The wires in the pic are the 2 wires from the new adaptor plug:
White-spliced to the white wire from original harness.
Red-to the ground post on the new internally regulated alt.

Then use ONE jump wire from I to F on the plug off of the old voltage reg., and trash that old volt. reg.

Please note: the black section on the white wire shown in the pic is the resistence diode that is built in to the adaptor, as per GM specs.

This is the easy and foolproof solution to this changeover. I know there are other ways, which include running wires, etc, but none as simple as this that I have seen. I've had it for 3 years, never a problem.

03-13-2003, 01:58 PM	#1
Reumster L.E.D. Freak Join Date: Jan 2002 Location: Polson MT Posts: 1,358	Wiring up a new enternally regulated alternator quick! Ok I just fried a battery because I was running with a bad voltage regulator, but I'm waiting on a new M&H harness that converts old style to internally regulated. I bought a internally regulated alternator and need to do a quick wire job. How do I do it? __________________ Specializing in Custom L.E.D. inserts. http://www.ccled.com/ Contact me @ blazer2wd1972@hotmail.com (406)675-8082 or Joel @ jmcwaters@eps-corp.net 1972 2wd Blazer, 350/700R4/3:73 posi, err & Custom L.E.D. inserts! LOL

03-13-2003, 02:21 PM	#2
68speedalert Semi-Senior Member Join Date: Feb 2003 Location: Washington, MO Posts: 390	I assume you are puttin on an older delco alt. If so, go to most parts stores and buy the 2 wire connector that plugs into the reg. on the alt. the large red on the conn goes to the large battery terminal on the alt. I'm sure you realize the large feed wire from the truck hasrness still goes there. Here's the tricky part. Some alts don't need a sense signal but others do. To the small white wire on the reg. connector you need to wire a key on hot wire with either a diode online or a 10 ohm resistor. If you don't, your truck won't shut off!!!!! Steve __________________ '68 50th Anniversery LWB Custom Fleetside, '77 305 v-8, turbo 350, factory speed alert (still works), '71 drivetrain w/front discs. Some call it ugly yellow, others call it Ochre '83 Jeep CJ-7, <80,000 miles, original owner '04 Chevy Suburban, 4x4, 2500, 6.0 ltr, Predator Diablo programmer '95 GMC K1500 Extended cab

03-13-2003, 02:30 PM	#3
Reumster L.E.D. Freak Join Date: Jan 2002 Location: Polson MT Posts: 1,358	I have the first internally regulated alternator, like a 73 or something. So the two prong connector coming of the alternator red wire needs to go to the power on the alternator also put the existing wire on the stock harness there to. The second white wire coming off the alternator connector goes to a acc. on the fuse box with a diode in line. Why so power won't back feed? I have plenty of schottky diodes only let power flow one direction. Will this due? Power to the alternator not back to the fuse box right? I have a 10ohm resistor to. Which is better? The diode right. __________________ Specializing in Custom L.E.D. inserts. http://www.ccled.com/ Contact me @ blazer2wd1972@hotmail.com (406)675-8082 or Joel @ jmcwaters@eps-corp.net 1972 2wd Blazer, 350/700R4/3:73 posi, err & Custom L.E.D. inserts! LOL

03-13-2003, 03:09 PM	#4
my new 72 faster, faster, faster Join Date: Dec 2001 Location: Houston ,Texas ,USA Posts: 1,354	That diode thing is pretty unnecessary. The red wire from the pigtail goes to the post on the back of the alternator, as well as the red bat. feed wire. Then the white wire goes to the white wire from the original alt. plug. The blue wire left over from the old alt. plug gets taped off. Then you use jumper wires to jump the wires on the voltage regulator connector like so. But since I forgot the picture, all you really have to do is jump the white to the brown on the volt reg connector. __________________ I'm going to Law School, wanna debate? It's good practice. Last edited by my new 72; 03-13-2003 at 03:17 PM.

03-13-2003, 03:13 PM	#5
my new 72 faster, faster, faster Join Date: Dec 2001 Location: Houston ,Texas ,USA Posts: 1,354	forgot the pic __________________ I'm going to Law School, wanna debate? It's good practice.

03-14-2003, 08:47 AM	#6
68speedalert Semi-Senior Member Join Date: Feb 2003 Location: Washington, MO Posts: 390	josh, good job on the jumping of wires at the reg connnector. I haven't switched my truck to int. reg yet even though I have the alt to do it. I'll remember your trick. My switchover was on an older jeep that I owned 20 years ago. Different regulators in the alt are sometimes different, depending on what they came off of. The one I had would back feed voltage to the ignition system after it started charging thru the white wire. So whenever i turned the key off, it didn't. When researching the wiring schematic on that gm car, they showed a 10 ohm resistor inline on that circuit. Back then I didn't know what a diode was so i put in the resistor and had no problems after. There are regulators you can buy that don't need the white wire(key on sense wire). reumster, if you still need to use the diode I would use it. Make sure it allows the voltage TO the reg. good luck. Steve __________________ '68 50th Anniversery LWB Custom Fleetside, '77 305 v-8, turbo 350, factory speed alert (still works), '71 drivetrain w/front discs. Some call it ugly yellow, others call it Ochre '83 Jeep CJ-7, <80,000 miles, original owner '04 Chevy Suburban, 4x4, 2500, 6.0 ltr, Predator Diablo programmer '95 GMC K1500 Extended cab

03-14-2003, 03:01 PM	#7
Reumster L.E.D. Freak Join Date: Jan 2002 Location: Polson MT Posts: 1,358	Thanks for the info but my M&H new harness from Early Classic got in, and I installed it so its allready done for me. Works great. This harness fit like a glove. Perfect. __________________ Specializing in Custom L.E.D. inserts. http://www.ccled.com/ Contact me @ blazer2wd1972@hotmail.com (406)675-8082 or Joel @ jmcwaters@eps-corp.net 1972 2wd Blazer, 350/700R4/3:73 posi, err & Custom L.E.D. inserts! LOL

03-14-2003, 03:24 PM	#8
Xzavior240 Registered User Join Date: Oct 2002 Location: enterprise kansas Posts: 230	ok I done went crosseyed trying to understand this. I see the part about the reg. on the rad. support. anyone got a pic or harness diagram showing the alt. ? because I have the alternator on the motor and everything. I just keep getting confused with jump this from here to that and cross this and add that and make this go to there. thanks dan __________________ 71 chevy C10 LWB 2WD runs and everything 79 chevy 1/2 ton Big Ten silverado gonna part it out since it left me walking. 69 f100 real good shape with lots of go go juice 89 plymouth reliant (daily driver) 86 thunderbird sitting in the weeds almost covered (anyone need parts?) WWW.xschunkofthenet.freeservers.com nothing there I promise " tell me I'm a sinner I got news for you. I spoke to god this morning and he dont like you" OZZY

03-14-2003, 06:14 PM	#9
barn9 Half a bubble off! Join Date: Jun 2000 Location: Winfield, Ks, USA Posts: 5,588	Xzavior240, I have the adaptor available to change over to the internally regulated alternator and eliminate the old voltage reg. It does have the diode wired into it also, which IS needed IMO. It's an easy changeover this way, and does not require any more than a couple wire splices. I'll add a pic of my alt to show the adaptor, but it doesn't show the connections very well. Attached Images __________________ Just call me LB. '71 Cheyenne, 402BB, hauls blondes, brunettes, or redheads.

03-14-2003, 06:49 PM	#10
Xzavior240 Registered User Join Date: Oct 2002 Location: enterprise kansas Posts: 230	ok youre right barn9 it doesnt show really well what I can see from it is the red wire hooking to the hot as well as the original wire and the white going onto the other side of that connection wheres the blue go? thanks for the attempt none the less __________________ 71 chevy C10 LWB 2WD runs and everything 79 chevy 1/2 ton Big Ten silverado gonna part it out since it left me walking. 69 f100 real good shape with lots of go go juice 89 plymouth reliant (daily driver) 86 thunderbird sitting in the weeds almost covered (anyone need parts?) WWW.xschunkofthenet.freeservers.com nothing there I promise " tell me I'm a sinner I got news for you. I spoke to god this morning and he dont like you" OZZY

03-15-2003, 04:07 AM	#11
barn9 Half a bubble off! Join Date: Jun 2000 Location: Winfield, Ks, USA Posts: 5,588	The wires from the original harness go like this: Blue-unused, just clip it and forget it. Black-unused Red-ground wire. White (switched lead)-spliced to the white wire on the adaptor plug. The wires in the pic are the 2 wires from the new adaptor plug: White-spliced to the white wire from original harness. Red-to the ground post on the new internally regulated alt. Then use ONE jump wire from I to F on the plug off of the old voltage reg., and trash that old volt. reg. Please note: the black section on the white wire shown in the pic is the resistence diode that is built in to the adaptor, as per GM specs. This is the easy and foolproof solution to this changeover. I know there are other ways, which include running wires, etc, but none as simple as this that I have seen. I've had it for 3 years, never a problem. __________________ Just call me LB. '71 Cheyenne, 402BB, hauls blondes, brunettes, or redheads.



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